How To Clean a Sprayer After Using Roundup: 5 Simple Steps

So you’ve taken the time to read the instructions, followed the mixing and application directions to the letter, and spent all day painstakingly eradicating all the weeds from your yard, only to be left with the arduous task of cleaning your sprayer before you safely stow it away until next year!

Once you know how to clean a sprayer after using Roundup, the task doesn’t seem so daunting, hazardous, complicated, or messy and can even be described as straightforward.

There are some pitfalls and potential dangers that everyone needs to be aware of upfront, however.

So whether you’re a seasoned professional or a novice, read on for my straight-talking and no-fuss guide on how to get it right so that your sprayer is as good as new for the next time you need it.

Key Takeaways

  • Properly cleaning your sprayer after using Roundup is crucial to avoid potential exposure to glyphosate and ensure safe storage. Cleaning both the tank and nozzle with warm, soapy water is the first step in maintaining your sprayer’s performance.
  • Glyphosate-containing products should never be poured down drains, as they can contaminate waterways and harm the environment. Instead, use approved methods for disposal, such as household hazardous waste programs or diluting and spraying the remaining product on permitted plants.
  • Leaving Roundup in your sprayer for extended periods can lead to clogs and render the sprayer unusable. To prevent this, measure and use only the necessary amount of product, and always clean the sprayer thoroughly after each use.

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Re-Using A Sprayer After Filling It With Glyphosate

The International Agency for Research on Cancer lists glyphosate as a probable carcinogen. However, its carcinogenic effects are a controversial topic.

It is believed that this herbicide can expose humans to long-term health risks, such as reproductive issues, liver disease, and pregnancy risks.

Therefore, not only do you need to protect yourself while using products containing glyphosate, but you also need to clean your sprayer thoroughly to avoid further exposure.

Cleaning a Sprayer After Using Roundup

Sprayers have two main parts: the tank and the nozzle. Whether it is a handheld or backpack sprayer, the cleaning process is similar, and the ultimate goal is the same: Remove all excess product from the sprayer, dispose of it safely, and clean the chamber of the sprayer thoroughly, both inside and out.

How To Clean Roundup Out of Backpack Sprayer

Backpack sprayers are the tools of choice if you have a large area to cover because they carry more content and are more flexible. Here is how to clean one:

Step 1: Empty the tank. If you have a small surplus of herbicide inside, spray it on the plants again until the nozzle runs dry.

Step 2: Dispose of Any Remaining Roundup Products. If you have a large amount of remaining liquid, you will need to pour it into a container for disposal.

Do this while still wearing protective clothing (at least gloves, a mask, and safety goggles).

Step 3: Clean The Sprayer Tank. Remove the nozzle along with the wand and the hose that draw liquid up from the tank.

Using a sponge, soap, and warm water, thoroughly clean the inside of the tank, the outside surface of the sprayer, and also the top section where the nozzle is screwed on.

Pour the soapy suds over unwanted plants (rather than down a drain) and repeat several times. Once the inside is clean, rinse all surfaces of the sprayer (inside and out) with fresh tap water.

Do not let the Roundup sit for a long time without cleaning. Wash it immediately after use to keep the chemical residues from building up on the tank surface.

Cleaning A Roundup Sprayer Nozzle

While it is possible to clean the tank using a sponge, the nozzle has unreachable internal cavities. Therefore, you need to flush it and begin the process using hot, soapy water.

Step 1: Fill The Tank Half Full of Water. Pour the water into the tank until it is halfway full, then spray it all out of the nozzle. Consider spraying close to where you were applying the herbicide to avoid contaminating other areas.

Step 2: Flush The Nozzle System. Next, flush the system using an ammonia-based cleaning solution. You can make your own formula by mixing 3ml of ammonia with 380ml of water.

Fill the tank halfway with the solution, then spray it out about five times to flush the wand and nozzle.

Step 3: Soak The Tank. Leave the remaining ammonia solution in the tank overnight, then spray it all out the next day.

Step 4. Rinse. Thoroughly rinse the nozzle by spraying it with hot water.

Step 5: Scrub. Using an old toothbrush, clean and scrub the nozzle with hot soapy water. Remembering to clean the hose and wand as well.

How To Neutralize Roundup in a Sprayer

Cleaning & diluting with water helps reduce the toxicity of Roundup, but the best neutralizer is ammonia.

As described in the steps above, you should leave the ammonia solution in the tank overnight, which helps to break down the herbicide.

If you have the money or just prefer not to make your own ammonia solution, you can buy commercial tank cleaners and detergents.

Arguably these are more effective at breaking down water and oil-soluble herbicides compared to household detergents and chemicals.

Can You Leave Weed Killer in a Sprayer?

Yes, you can. However, it does depend on the amount of time you are leaving it there. If there is an interruption due to weather, it is okay to leave the chemicals in the tank, provided you resume spraying after a few hours.

You only have to agitate the herbicide in the tank to mix up the chemicals.

However, leaving it for more than a few hours will lead to blockages. Heat and cold tend to make the Roundup clump up, forming a gel that clogs the nozzles and lines the tank.

This is likely to result in being unable to use your sprayer again in the future.

The best practice is to measure or approximate the exact amount you need so that you spray everything in the tank making it easier to clean at the end of the day.

If you have to continue spraying the next day, at least wash the tank using hot soapy water. Neutralize with ammonia once you have completed the spraying project.

Getting Rid of Old Weed Killers

Various US states run household hazardous waste programs with at least two collection events per year. These programs offer residents an opportunity to safely dispose of RoundUp and other harmful chemicals.

For instance, Tennessee runs these events in the fall and spring to avoid harsh weather, while in California, there are various collection facilities in each city.

However, if you are a farmer or commercial pesticide user, you cannot use the standard household programs.

Most states run clean sweep programs that handle the disposal of large quantities of pesticides and herbicides. Details of this program vary by state.

That said, you should try to avoid generating if at all possible by buying only enough Roundup for your garden. If you have a surplus, share it with your gardening friends or family. Make sure any remaining chemical goes to good use.

Can You Pour Roundup Down the Drain?

No. Pouring Roundup down a drain ends up contaminating the waterways. Even wastewater treatment plants cannot neutralize such chemicals, so the runoff will end up seeping into the ground.

Eventually, in some way, it will end up back in your home, as we get our freshwater mostly from rivers and boreholes.

If there is no safe disposal method available, dilute the Roundup and then spray it onto permitted plants. Check the label instructions to get this information.

Final Thoughts: Cleaning Glyphosate From a Sprayer?

Glyphosate weed killers are super beneficial to farming and gardening, but you must handle them with care and with environmental safety in mind.

Whichever sprayer you use to apply Roundup, make sure you clean it the right way to ensure safety and long-lasting use.

Although these are the general cleaning and disposal directions, it is vital to check the manufacturer’s instructions to implement the best practices.

You might also enjoy reading:

10 Best Pump & Backpack Weed Sprayers Review + Buyers Guide

Can You Spray Weed Killer On Wet Grass | Does It Work?

FAQs About How To Clean A Sprayer After Using Roundup

How Do You Clean Roundup Out Of A Sprayer? 

To clean Roundup out of a sprayer, follow these steps:

1. Empty the tank by spraying any excess herbicide on plants.

2. Dispose of leftover Roundup properly while wearing protective gear.

3. Remove the nozzle, wand, and hose, then clean inside the tank, outside, and nozzle with warm, soapy water.

4. Rinse all surfaces thoroughly to prevent chemical residues.

Can Roundup Be Cleaned Out Of A Sprayer?

Yes, Roundup can be cleaned out of a sprayer using proper cleaning procedures. Thorough cleaning helps prevent exposure to glyphosate residues.

Can You Use The Same Sprayer You Had Roundup In For Other Things?

It’s advisable not to use the same sprayer for different substances after containing Roundup. Cross-contamination risks exist due to potential residual glyphosate, which can affect other applications.

Does Vinegar Wash Off Glyphosate?

Vinegar may not effectively wash off glyphosate. Proper cleaning with water and detergent is recommended.